The present invention relates to a manual transmission of a vehicle and more particularly to a reverse shift device that can prevent deterioration of reverse shift feeling and reduce noise.
As shown in FIGS. 1 and 2, there are general ways to perform a reverse shift in a manual transmission. According to a method shown in FIG. 1, the reverse shift can be achieved by meshing reverse idle gears (not shown) between the reverse drive gear 102 provided in an input axle 100 and a reverse driven gear 106 provided in first and second shifting sleeves 104 of an output axle. At this time, in order to mesh the reverse idle gears, the gravitational revolution of the input axle 100 is stopped by using a synchronizer 108 to get the input axle 100 connected to a transmission case 110. However, in this method, the synchronizer 108 is applied to the input axle 100, thereby increasing frictional resistance of the input axle 100, which may deteriorate shift feeling in a forward shift.
Next, in the method shown in FIG. 2, a reverse idler gear 208 is always meshed between a reverse drive gear 202 formed at an input axle 200 and a reverse driven gear 206 installed at an output axle 204. The reverse driven gear 206 is connected by means of a bearing 210 with the output axle 204 and then, connected by a reverse synchronizer 212 with the output axle 204. Since the reverse idler gear 208 is continuously meshed between the reverse drive gear 202 and the reverse driven gear 206, the structure shown in FIG. 2 may easily cause rattle noise when a vehicle stops or while the vehicle runs.
Also, the reverse shift devices shown in FIGS. 1 and 2, respectively, include the synchronizers 108, 212 at the input and output axles 100, 204, to thereby make the transmission longer and reduce the carry capability of a vehicle.
It is one object of the present invention to solve the aforementioned problems and provide a reverse shift device of a manual transmission that can, among other things, reduce the total length of the transmission, improve shift feeling and decrease noise.
Thus, according to a preferred embodiment of the present invention, there is provided a reverse shift of a manual transmission including an idle axle fixed at a transmission case and an idle synchronizer installed at the idle axle for switching the state of transmission of rotational force of an input axle to an output axle at the time of forward-reverse shifts. According to a further preferred embodiment a synchronizer is provided within the idle axle to reduce length.
In an alternative preferred embodiment an idle synchronizer may include an idler clutch gear installed at the idle axle for free rotation, an input gear mounted at the input axle to be meshed to the idler clutch gear, a reverse synchronizer ring installed at the idle axle beside the idler clutch gear, and an idler sleeve spline-coupled with the idle axle to be movable to the axial direction.
Further, an idler gear rotatively installed at the idler sleeve to switch between simultaneously meshing with the reverse drive gear of the input axle and the reverse driven gear of the output axle according to the axial movement of the idler sleeve. Preferably a synchro-ring operating means pushes the reverse synchronizer ring tightly to the idler clutch gear when the idler sleeve moves to the direction of enabling the idler gear to be meshed with the reverse drive gear and the reverse driven gear.
In a further alternative embodiment, a reverse shift device according to the invention includes an idler gear assembly movable between an idle position and a reverse engaged position in response to a gear shift, a reverse drive gear mounted on an input shaft cooperating with the idler gear assembly in the reverse engaged position, and a synchronizer assembly operatively linked to the idler gear assembly and cooperating with the input shaft to stop rotation of the input shaft in response to movement of the idler gear assembly to the reverse engaged position. Preferably, the idler gear assembly is made up of an idler sleeve moveable between the idle position and the reverse engaged position and an idler gear rotatably mounted on the idler sleeve, wherein the idler gear engages the reverse drive gear and a reverse driven gear in the reverse engaged position. In a further preferred embodiment, the synchronizer assembly comprises a second idler gear cooperatively engaging the input shaft, a synchronizing ring disposed adjacent the second idler gear to act thereon and a linkage between said idler sleeve and the synchronizing ring to force the ring against the second idler gear in response to movement of the idler sleeve to the reverse engaged position. Thus, the synchronizing ring acts on the second idler gear to stop rotation of the input shaft. Preferably the linkage may comprise a pivot lever having an end captured by the idler sleeve and an opposite end bearing against the synchronizing ring.